Nuclear fusion is a way to get energy the way stars do: by fusing light hydrogen nuclei into helium. It needs a tiny amount of fuel, produces no carbon dioxide and no long-lived high-level waste either. For humanity it is a chance at almost inexhaustible energy; for business today it is a strategy horizon: the first plants — not before the end of the decade, and for now it is labs and construction sites.
How it works
Hydrogen nuclei carry the same charge and repel each other. To make them fuse, they have to collide at enormous speed — which means heating the gas to a hundred million degrees. At that temperature matter becomes plasma: electrons are torn away from nuclei. Most often the heavy isotopes of hydrogen are used — deuterium and tritium. When they fuse, they produce a helium nucleus and a fast neutron, and the difference in mass turns into energy by the formula E = mc² — millions of times more than from burning the same amount of fuel.
No wall can withstand hundreds of millions of degrees, so the plasma is held by a magnetic field. A tokamak is a doughnut of magnets: charged particles race around along the field lines and do not touch the walls. The superconducting magnets are cooled almost to absolute zero, while a few meters away burns plasma hotter than the center of the Sun. China’s EAST tokamak held plasma for 1,066 seconds, and at SPARC the magnets are being installed for first plasma in 2027.
The main question is gain: the machine has to give out more energy than it spends on heating and magnets. The energy is carried off by neutrons: they fly out of the plasma, strike the wall — the blanket — and heat it, and from there it is the familiar steam and turbine. In the same blanket, tritium will be bred from lithium, because there is almost none of it in nature. Materials age under the neutron flux, and engineers still have to prove that a plant can run for years, not minutes.
Where it already works
- China’s EAST tokamak: plasma for 1,066 seconds, January 2025.
- SPARC: first plasma planned for 2027, energy gain — later.
- China’s BEST tokamak is being built for 2027.
- Helion plans to supply fusion energy to Microsoft in 2028 — low confidence.
What to consider
- There is no fusion electricity on the grid yet: the first plants — not before the end of the decade.
- Companies’ dates are plans with medium and low confidence, not a delivery schedule.
- Large volumes of fusion energy on the grid by 2035 — low confidence.
- For energy today — solar, storage and geothermal; fusion is a strategy horizon.